Marked pharmaceutical tablet



Jan. 2, 1962 R. Y. SANDERS, JR

MARKED PHARMACEUTICAL TABLET Original Filed Feb. 6, 1956 [N V EN T 0R. Kay X JA Nos/rs, J r.

United States Patent 3,015,610 MARKED PHARMACEUTICAL TABLET Roy Y. Sanders, Jr., 745 Lebrun Road, Buffalo 21, N.Y. Continuation of application Ser. No. 563,666, Feb. 6, 1956. This application Nov. 4, 1957, Ser. No. 698,020 5 Claims. (Cl. 167-82) This invention relates generally to the pharmaceutical art, and more specifically to a new and useful tablet coating and to the ink printing of indicia on pharmaceutical tablets.

This application is a continuation of my pending application Serial No. 563,666, filed February 6, 1956, now

abandoned.

The importance of providing pharmaceutical tablets with a clearly visible identifying marking, to prevent spurious imitations and substitutions, is well illustrated by the significant volume of business which has been lost by some manufacturers because of such imitations and substitutions. Accordingly, manufacturers have resorted to adding trace elements to their formulae, imparting odd shapes to their tablets, embossing and/or engraving identifying marks on uncoated tablets, and to the use of distinctive colors, to positively identify their product and to combat counterfeiting and substitution.

However, the trace elements are not normally visible, the use of particular shapes and colors is not always satisfactory because they are too easily duplicated, and conventional embossing and engraving techniques of marking have certain disadvantages and furthermore are not particularly suitable for use with coated tablets of the type which have a medicinal core covered with suc cessive undercoats, smoothing coats and finishing coats.

In addition, coated tablets must be pharmaceutically elegant if they are to enjoy consumer approval, and any identifying marking used therewith must not detract from the pharmaceutical elegance of the finished product.

In my pending application Serial No. 333,147, filed January 26, 1953, I disclose a pharmaceutical tablet marking technique wherein ink indicia is printed on the coated medicinal core beneath an outer coating of transparent material covering the coated core and the indicia printed thereon. I also disclose therein the specific technique of printing the mark on a coating having a resin base, such as shellac, with an ink having the same resin base. This technique provides a marked tablet possessing the requisite pharmaceutical elegance and wherein the marking is protected and therefore not subject to being chipped or flaked oif during handling.

In another pending application S.N. 539,111, filed October 7, 1955, I disclose the concept of ink printing on a resinous coating containing a lubricative plasticizer, with its attendant advantages, together with certain specific formula for such coating and certain tablet printing techniques. As disclosed therein, a lubricative plasticizer being edible, soluble in alcohol and compatible with the resinous outer indicia receiving coating is selected from long-chain molecular weight fatty alcohols such as stearyl or cetyl alcohol and 'glyceridcs of higher fattyacids. As to the glycerides, the monoglycerides or acetylated monoglycerides are preferred over triglycerides which are operable but not preferred.

However, under certain circumstances a coating comprising a resin base such as shellac is too susceptible to temperature conditions apt to be encountered in storage rCe and shipment. For example, when such tablets are stored in hot climates or under hot temperature conditions the shellac coating on which the identifying indicia is printed is apt to melt and run, thereby producing a tendency for the tablets to adhere to each other and also distorting the indicia, thereby ruining the pharmaceutical elegance of the printed tablets.

Accordingly, it is a particular object of this invention to provide a resinous coating more resistant to the hot temperature conditions which may be encountered in storage and shipment.

It is also an object of this invention to provide a particularly desirable resinous coating or lacquer which is of a completely compatible and homogeneous nature and which has a pharmaceutically elegant appearance.

In a presently preferred form, the indiciais printed on a resinous lacquer coating having shellac as its base, using a shellac base ink carried in a spirit solvent, thereby obtaining a good bond between the ink and the coating on which it is printed.

In accord with one aspect of this invention, I include with the shellac base of the resinous coating an additive material for the purpose of increasing the blocking or tack point of the coating above that of the shellac.

Also, in another aspect thereof I include in the aforesaid lacquer coating a lubricative plasticizer, and I preferably add certain further substances for the purpose of clarifying the coating solution and rendering it completely compatible, to provide a clear and homogeneous coating thereby adding to the pharmaceutical elegance of the product.

The foregoing and other objects, advantages and characterizing feature of my invention will become clearly apparent from the ensuing detailed description, taken together with the accompanying drawing forming a part thereof wherein:

FIG. 1 is a top plan view of a pharmaceutical tablet marked in accord with my invention, certain parts broken away for greater clarity; and

FIG. 2 is a transverse sectional view taken about on line H-II thereof.

Referring now to the accompanying drawing, in the presently preferred form of my invention the tablet, generally designated 1, comprises a conventional medicinal core 2 which is coated in a known manner with the usual subcoats comprising, for example, a mixture of gelatin, sugar and dusting powder until the corners of the core are well covered and the tablet is well rounded and in proper proportion, smoothing coats comprising, for example, a white undercoating or grossing syrup for white tablets, or a plain coating syrup for colored tablets until the tablets are well rounded and smooth, and finishing coats comprising, for example, either plain or colored coating syrups. While the foregoing constitute, in reality, a large number of coats, for simplicity and ease of illustration I show them combined into a single coat 3, and this is what is referred to herein by the term coated medicinal core. v

The coated medicinal core 2, 3 is covered with a resinous coating 4, containing the additive material, the indicia marking 5 is ink printed on the coating 4, and the coating 4 and marking 5 preferably are covered with a transparent protective coating 6. a

More specifically, in accord with my invention the coating 4 comprises shellac, and. an additive material water.

compatible with the shellac and having a higher melting point than that of the shellac, in an amount sufficient to increase the blocking or tack point of the coating sub stantially above that of the shellac.

By way of example, a presently preferred lacquer coating 4 in accord with this invention is as follows, the quantities given being based on a total mixture of approximately four gallons of resinous coating compound in liquid form:

Zein powder: 1 pound, 11 ounces, 189 grains Ethyl alcohol: 4 pints Urea: 2 ounces, 325 grains Water: 6 ounces Dewaxed shellac, 4 lb. cut (2.8 lbs. dry shellac in sufficient alcohol to make one gal.) 6 pints Myvacet (type 940 Distillation Products Div. of Eastman Kodak Company): 360 cc.

In mixing this coating compound, the zein powder is dissolved in the alcohol, and the urea is dissolved in the These solutions then are mixed and the shellac and Myvacet are added thereto. Alcohol is added as required to bring the total mixture to four gallons. If a thinner coating is required, the solution is diluted with more alcohol.

This provides a shellac base, resinous coating, but with the zein powder increasing the blocking or tack point of the coating substantially above that of straight shellac (100-l20 R), and with this higher blocking or tack point the resinous coating is capable of withstanding storage under extremely high temperatures probably exceediug any which are apt to be encountered.

Another example of an additive material, suitable for purposes of my invention, is ethyl cellulose, although the zein is presently preferred.

The Myvacet is an acetylated higher fatty acid monoglyceride which functions as a lubricative plasticizer, thereby plasticizing the shellac base coating to at least delay setting thereof until the mark is ink printed thereon, and also lubricating the tablet to assist in the printing thereof, as set forth in my pending application Serial No. 539,111, filed October 7, 1955. As disclosed therein, other preferred lubricative plasticizers include higher fatty alcohols and monoglycerides and acetylated monoglycerides. Triglycerides of higher fatty acids are operable but not preferred. Myvacet-940 (Distillation Products, Inc.) from prime lard contains two acetic acid groups and one long-chain fatty acid per fat molecule (diacetyl glyceryl monostearin, diacetyl glyceryl monolaurin).

The urea and water are added to provide a very clear and compatible solution, whereby if the coating is applied over a color coat it will not hide or cloud the color thereof but instead will preserve and even enhance the pharmaceutical elegance of the tablet.

Also, the Myvacet appears to improve the glossy, elegant appearance of the coating, and enhance the color of the coating therebeneath.

In practice, the resinous coating 4 is applied over the coated medicinal core in the usual tumbling type coating pan, except that once the tablets are wet and covered I prefer to stop the coating pan and then turn the pan by hand every two or three minutes until the tablets are dry.

After the resinous lacquer coating is partially dried, and preferably before it has set, I print the indicia thereon in ink which preferably is of a distinguishing color compared to the finishing coat which in the preferred form is clearly visible through the resinous coating. The printing is done, for example, by an offset proces in a machine wherein the tablets are carried for example on an endless conveyor having rows of springbacked pockets receiving the tablets from a feed hopper and conveying them beneath a rubber printing roller, which receives the ink indicia from a suitable die and transfers the ink indicia to the tablets, from which the tablets are conveyed to a discharge chute.

After the indicia is printed, the marked tablets are dried until the coating 4 and ink indicia 5 set, which might take, for example, five days unless forced drying is used. This is to ensure that the printed mark will adhere to the resinous coating and not smudge or rub off during the polishing operation or upon handling if the polishing step is omitted.

Once the coating 4 and ink indicia 5 have set, a transparent, and preferably polished protective outer coat 6 can be applied thereover, although under some conditions it might be possible, with the coating 4 of this invention, to dispense with the outer coat 6 and still have a pharmaceutically elegant product.

If the outer coat 6 is used, it can comprise cana'uba Wax, beeswax, or the like, applied over the coating 4 and indicia 5 in polishing pans of the usual type. The coating 6 adds to the polished and pharmaceutically elegant appearance of the marked tablet, and protects the mark 5 against rubbing, chipping or flaking ofi upon contact with other tablets, or with its container, during handling thereof.

While this coating 4 has been developed particularly for use with the ink printing of identifying indicia thereon, it is believed that a resinous coating according to this invention might also find use as a moisture barrier to protect any hygroscopic matter beneath the coating, and might therefore find use apart from the printing of indicia thereon.

Also, while I presently contemplate a clear resinous coating, to provide an elegant appearance and to permit a color coating therebeneath to show therethrough, I feel that it might be possible to color this resinous coating and use it also as a color coat.

Accordingly, it is seen that my invention fully accomplishes the aforesaid objects, and while only a few specific examples have been given I do not necessarily intend that my invention be limited thereto but instead I intend that my invention be defined by the appended claims.

Having fully disclosed and completely described my invention, what I claim as new is:

1. A marked pharmaceutical tablet comprising a coated medicinal core including a plurality of foundation subcoats, an ink receptive coating thereover comprising a major amount of shellac, a lubricative plasticizer and ethyl cellulose and ink indicia printed on said layer.

2. A marked pharmaceutical tablet according to claim 1 wherein said ink indicia is a shellac based ink.

3. A marked pharmaceutical tablet according to claim 1 wherein a transparent overcoating is applied over said ink indicia.

4. A marked pharmaceutical tablet according to claim 1 wherein the lubricative plasticizer is an acetylated higher fatty acid monoglyceride.

5. A marked pharmaceutical tablet according to claim 1 wherein minor amounts of urea and water clarifiers are included in the ink receptive layer.

References Cited in the file of this patent UNITED STATES PATENTS 200,589 Warner Feb. 19, 1878 456,772 Osborne July 28, 1891 2,089,209 Keuffel Aug. 10, 1937 2,102,623 Hansen Dec. 21, 1937 2,128,973 Tisdale Sept. 6, 1938 2,245,100 Bernstein June 10, 1941 2,338,151 Weber Jan. 4, 1944 2,340,913 Weber Feb. 8, 1944 2,360,081 Stewart Oct. 10, 1944 2,360,382 Weber Oct. 17, 1944 2,421,291 Schmutzler May 27, 1947 2,433,244 Springett Dec. 23, 1947 2,865,810 Sanders Dec. 23, 1958 (Other references on following page) FGREIGN PATENTS Australia Jan. 11, 1940 OTHER REFERENCES Clarkson: Tablet Coating, Drum and Cosmetic Industry, New York, N.Y., 1951, pages 48-50, 55-57.

Rowell: The Art of Coating Tablets, Part I, Drug and Cosmetic Industry, vol. 63, No. 3, September 1948, pages 308-310, 411-414.

Rowell: The Art of Coating Tablets, Part II, Drug and Cosmetic Industry, vol. 63, No. 4, October 1948, pages 458-460, 549, 551.

Herstein: Properties of Films Containing Ethyl Cellulose and Shellac, B. Ch. E. Thesis, 1935-1936, Brooklyn Polytechnic Institute.

Kamath et al.: Lac-Ethyl Cellulose Lacquers, London Shellac Research Bureau, Technical Paper No. 27, March 1945, 23 page pamphlet.

Mattiello: Protective and Decorative Coatings, John Wiley and Sons, Inc, New York, 1941, volume 1, page 273 thru 275, esp. at p. 274.

Chatfield: Varnish Constituents, Leonard Hill Ltd., London, 3rd Ed., 1953, pp. 232-239, 249-250.

Bhattacharya: Lac-the Multipurpose Resin (6 page reprint of original, from The Manufacturer, April 1951), Miscellaneous Pamphlets, Leaflets, etc. Indian Lac Reseach Institute. T? 938 16m. 

1. A MARKED PHARMACEUTICAL TABLET COMPRISING A COATED MEDICINAL CORE INCLUDING A PLURALITY OF FOUNDATION SUBCOATS, AN INK RECEPTIVE COATING THEREOVER COMPRISING A MAJOR AMOUNT OF SHELLAC, A LUBRICATIVE PLASTICIZER AND ETHYL CELLULOSE AND INK INDICIA PRINTED ON SAID LAYER. 